ATHENS , Greece -LRB- CNN -RRB- -- Protesters clashed with riot police and 10,000 people marched on parliament in Greece as a 15-year-old boy killed by police was buried Tuesday .

Tear gas fills the air near where the teen 's funeral service was held .

Thousands paid their respects to Alexandros Grigoropoulos at his funeral , but a small number of the protesters there grew violent at the end of the ceremony .

Riot police lined up as night fell and a reasonably peaceful candlelight vigil was held in central Athens .

Some 10,000 people marched on the country 's parliament Tuesday to express their anger at the teenager 's death , and also other issues like the economy , jobs , and allegations that the government is corrupt .

Groups clashed with riot police at the parliament and across central Athens .

Street riots started over the weekend after Athens police killed 15-year-old Alexandros Grigoropoulos on Saturday . Police said six young protesters pelted a police patrol car with stones , and the teen was shot as he tried to throw a fuel-filled bomb at the officers .

The shooting occurred in a neighborhood where there have been regular clashes with police , but it immediately sparked clashes and riots in Athens and Thessaloniki , the country 's second-largest city . The violence then spread to other municipalities . Watch iReporter John Kountouris ' videos of the violence ''

The events have exacerbated the unpopularity of the ruling party and left Greek Prime Minister Konstandinos Karamanlis scrambling to shore up support . Watch crowds gathered for funeral ''

On Tuesday , he met with President Karolos Papoulias and cabinet members before briefing political leaders on the country 's security situation .

Opposition leader George Papandreou of the left-wing PASOK party said : `` The country does not have a government that can protect its citizens , their rights , or their safety .

`` I told Mr. Karamanlis that our society , our citizens are experiencing a multiple crisis : an economic crisis , a social crisis , an institutional crisis , and a crisis of values . And the government is unable to address these crises ; they have lost the confidence of the Greek people . '' See images of anarchy on Greek streets ''

Karamanlis ruled out early elections and called for all political parties to stand together against violence .

`` It 's our responsibility to maintain a united stance against illegal acts , '' he said in statement . `` We must condemn in the strongest terms , with pure reason and not minced words - the violence , pillaging , and vandalism , that hampers social peace . ''

The government called on union leaders to cancel a national strike planned for Wednesday , fearing it could lead to further violence . But the labor movement refused , saying the action was planned before the shooting of the boy and was unrelated to it .

Cleaning crews worked for hours early Tuesday to clear the mess left by the riots , but evidence of the violence remained . In some places , entire rows of shops still have broken windows . iReport.com : Are you there ? Share photos , video of rioting

The mayor of Athens asked residents not to dispose of garbage for a day because many of the city 's trash bins were destroyed in the violence .

Karamanlis vowed again Tuesday that those responsible for the violence would be punished .

`` I assured the president that no leniency will be tolerated in holding people accountable , '' he told reporters . `` No one has the right to use this tragic incident as an alibi for actions of raw violence . ''

Athens police said 12 policemen were injured in Monday 's violence and 87 people were arrested . There were 10 flashpoints across Athens where police confronted rioters , police said . Watch protesters clash with police ''

Many of the young people who rioted holed up at universities , taking advantage of a decades-old rule that bars police from entering university grounds . The rule came into force after tanks crushed a 1973 student uprising protesting the ruling military junta .

The dean of Athens University resigned Tuesday as a result of the students ' violent behavior .

Public and private schools and universities across the country were shut again Tuesday . Watch as iReporter witnesses the clashes

Demonstrators torched government buildings and the offices of the ruling conservative party in central Athens . They also set cars and trash containers ablaze .

Monday , young demonstrators barricaded streets in Athens and Thessaloniki and hurled gasoline bombs as they battled police . Clouds of tear gas hung over the capital as police tried to disperse the crowds .

The police officer who fired the fatal shot at the teenage boy has been charged with `` manslaughter with intent '' and suspended from duty , police said , adding that a second police officer was arrested Saturday on criminal accessory charges .

Government officials , including the interior minister , have condemned the shooting .

Authorities conducted an autopsy on the boy Monday in an effort to clarify the circumstances of the shooting , but the boy 's family has called in their own investigators to verify state findings , the Athens coroner told CNN .

CNN 's Eileen Hsieh and Phil Black , and Journalist Anthee Carassava , contributed to this report

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Funeral held for 15-year-old shot dead by police in Greece

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Anti-government violence flares at funeral and outside parliament

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Protesters are angry at government policies as well as the teen 's death

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Alexandros Grigoropoulos ' death sparked riots across Greece